Silencing of Annexin A1 suppressed the apoptosis and inflammatory response of preeclampsia rat trophoblasts

Diabetic microenvironment deteriorates the regenerative capacities of adipose mesenchymal stromal cells

BACKGROUND

Type 2 diabetes is an endocrine disorder characterized by compromised insulin sensitivity that eventually leads to overt disease. Adipose stem cells (ASCs) showed promising potency in improving type 2 diabetes and its complications through their immunomodulatory and differentiation capabilities. However, the hyperglycaemia of the diabetic microenvironment may exert a detrimental effect on the functionality of ASCs. Herein, we investigate ASC homeostasis and regenerative potential in the diabetic milieu.

METHODS

We conducted data collection and functional enrichment analysis to investigate the differential gene expression profile of MSCs in the diabetic microenvironment. Next, ASCs were cultured in a medium containing diabetic serum (DS) or normal non-diabetic serum (NS) for six days and one-month periods. Proteomic analysis was carried out, and ASCs were then evaluated for apoptosis, changes in the expression of surface markers and DNA repair genes, intracellular oxidative stress, and differentiation capacity. The crosstalk between the ASCs and the diabetic microenvironment was determined by the expression of pro and anti-inflammatory cytokines and cytokine receptors.

RESULTS

The enrichment of MSCs differentially expressed genes in diabetes points to an alteration in oxidative stress regulating pathways in MSCs. Next, proteomic analysis of ASCs in DS revealed differentially expressed proteins that are related to enhanced cellular apoptosis, DNA damage and oxidative stress, altered immunomodulatory and differentiation potential. Our experiments confirmed these data and showed that ASCs cultured in DS suffered apoptosis, intracellular oxidative stress, and defective DNA repair. Under diabetic conditions, ASCs also showed compromised osteogenic, adipogenic, and angiogenic differentiation capacities. Both pro- and anti-inflammatory cytokine expression were significantly altered by culture of ASCs in DS denoting defective immunomodulatory potential. Interestingly, ASCs showed induction of antioxidative stress genes and proteins such as SIRT1, TERF1, Clusterin and PKM2.

CONCLUSION

We propose that this deterioration in the regenerative function of ASCs is partially mediated by the induced oxidative stress and the diabetic inflammatory milieu. The induction of antioxidative stress factors in ASCs may indicate an adaptation mechanism to the increased oxidative stress in the diabetic microenvironment.

Research progress on the STAT signaling pathway in pregnancy and pregnancy-associated disorders

Signal transducer and activator of transcription (STAT) proteins, pivotal regulators of signaling cascades, undergo activation in response to the stimulation of cytokines and growth factors, and participate in biological processes, including inflammation, immune responses, cell proliferation, and differentiation. During the process of pregnancy, STAT signaling is involved in regulating embryonic implantation, endometrial decidualization, and establishing and maintaining maternal-fetal immune tolerance. Increasing evidence suggests that aberrant STAT signaling contributes to the occurrence and development of pregnancy disorders, including repeated implantation failure (RIF), preeclampsia (PE), recurrent spontaneous abortion (RSA), preterm birth (PTB) and gestational diabetes mellitus (GDM). Elucidating the molecular mechanisms of the STAT signaling pathway holds promise for further understanding the establishment and maintenance of normal pregnancy, and thereby providing potent targets and strategic avenues for the prevention and management of ailments associated with pregnancy. In this review, we summarized the roles of the STAT signaling pathway and its related regulatory function in embryonic implantation, endometrial decidualization, and maternal-fetal immune tolerance. In conclusion, in-depth research on the mechanism of the STAT signaling pathway not only enhances our understanding of normal pregnancy processes but also offers STAT-based therapeutic approaches to protect women from the burden of pregnancy-related disorders.

Screening and functional analysis of the differential peptides from the placenta of patients with healthy pregnancy and preeclampsia using placental peptidome

Molecular peptides play an extensive range of functions in the human body. However, no previous study has performed placental peptidome profiling. In the present study, 3,941 peptides from human placental tissues were identified using peptidomics. Compared to healthy pregnant women, there were 87 and 129 differentially expressed peptides (DEPs) in the mild and severe preeclampsia groups, respectively. In the mild PE group, 55 and 34 DEPs had high and low expressions, respectively. In comparison, in the severe PE group, 82 and 47 DEPs had high and low expressions, respectively. Functional analysis of the precursor proteins of DEPs by gene ontology suggested that they are primarily involved in focal adhesion, extracellular matrix-receptor interaction, tight junction, and extracellular matrix. Network analysis using ingenuity pathway analysis software showed that the precursor proteins of DEPs were primarily related to the transforming growth factor-β (TGF-β)/Smad signaling pathway. Further molecular docking experiments showed that the AASAKKKNKKGKTISL peptide (placenta-derived peptide, PDP) derived from the precursor protein IF4B could bind to TGF-β1. Therefore, our preliminary results suggest that the actions of PDP may be mediated through the TGF-β1/Smad signaling pathway. Our results demonstrate that the placental bioactive peptides may regulate the placental function during PE progression.

HDAC5 inactivates CYR61-regulated CD31/mTOR axis to prevent the occurrence of preeclampsia

Our study was to pinpoint the significance of histone deacetylase 5 (HDAC5) affecting the pathogenesis of preeclampsia (PE) via CD31/mammalian target of rapamycin (mTOR) axis by regulating cysteine-rich angiogenic inducer 61 (CYR61). Expression of HDAC5, CYR61, and CD31/mTOR in placental tissues of patients with PE and trophoblast cells HTR-8/SVneo cells was determined first followed by their interaction analysis. Following different transfection, the significance of HDAC5 in cell functions was assayed in relation to CYR61 and CD31/mTOR. An in vivo PE mouse model was constructed for further validation. The clinical tissue and in vitro cell experimentations discovered that HDAC5 was downregulated in placental tissues of PE patients and trophoblast cells, while CYR61, CD31, mTOR, and p-mTOR displayed upregulation. After overexpression of HDAC5, trophoblast cell functions were enhanced. HDAC5 reduced the acetylation enrichment of H3K27 to inhibit the expression of CYR61. Furthermore, CYR61 promoted the activation of CD31/mTOR axis, thereby inhibiting HTR-8/SVneo cell functions. The in vivo rat model confirmed the above alterations. Taken together, HDAC5 contributes to downregulation of CYR61 through histone deacetylation, inactivating CD31/mTOR axis, which prevents the occurrence and development of PE.

ANNEXIN A1: Roles in Placenta, Cell Survival, and Nucleus

The unbiased approaches of the last decade have enabled the collection of new data on the biology of annexin A1 (ANXA1) in a variety of scientific aspects, creating opportunities for new biomarkers and/or therapeutic purposes. ANXA1 is found in the plasma membrane, cytoplasm, and nucleus, being described at low levels in the nuclear and cytoplasmic compartments of placental cells related to gestational diabetic diseases, and its translocation from the cytoplasm to the nucleus has been associated with a response to DNA damage. The approaches presented here open pathways for reflection upon, and intrinsic clarification of, the modulating action of this protein in the response to genetic material damage, as well as its level of expression and cellular localization. The objective of this study is to arouse interest, with an emphasis on the mechanisms of nuclear translocation of ANXA1, which remain underexplored and may be beneficial in new inflammatory therapies.

Knockdown of Annexin A1 induces apoptosis, causing G2/M arrest and facilitating phagocytosis activity in human leukemia cell lines

Annexin A1 (ANXA1) is an endogenous protein involved in the control of proliferation, cell cycle, phagocytosis, and apoptosis in several types of cancer. To investigate the effects of ANXA1 knockdown in leukemia cells, transfection with specific ANXA1 siRNA was performed. Cell cycle and apoptosis were analyzed using flow cytometry and a mechanism involving caspases and Bcl-2 was quantified using Western blotting. Phagocytosis activity was evaluated using hematoxylin & eosin staining. The ANXA1 expression was significantly downregulated after the knockdown and apoptosis was induced in tested cells. The expression of caspase-9 and -3 increased in U937 and Jurkat cells respectively. Bcl-2 expression was downregulated in K562 and Jurkat cells while upregulated in U937. The number of leukemic cells arrested at the G2/M phase and the phagocytosis index were significantly increased in transfected cells. This suggests that ANXA1 knockdown might be a potential approach in the therapeutic strategy for leukemia.

MiR-133b regulates oxidative stress injury of trophoblasts in preeclampsia by mediating the JAK2/STAT3 signaling pathway

Preeclampsia (PE) is a pregnancy-related syndrome. Aberrant placental microRNAs (miRNAs) expression might associate with PE, including miR-133b. However, its role in the pathogenesis of preeclampsia remains elusive. Therefore, this study explored the role of miR-133b in oxidative stress injury of trophoblasts in preeclampsia (PE) by mediating the JAK2/STAT3 signaling pathway. Placental tissues were collected from PE patients to detect the expression of miR-133b and JAK2/STAT3. Then, in vitro experiments were performed on human extravillous trophoblast-derived HTR-8/SVneo cells, which were divided into Normal, hypoxia/reoxygenation (H/R), H/R + miR-NC, H/R + miR-133b inhibitor, H/R + JAK2 siRNA and H/R + miR-133b inhibitor + JAK2 siRNA groups. Cell invasion and migration abilities were detected by Transwell and wound healing assays, while apoptosis was detected by flow cytometry. The intracellular oxidative stress levels were also measured. Furthermore, the expression of miR-133b and the JAK2/STAT3 pathway was determined by qRT-PCR and Western blotting. We found that miR-133b was up-regulated, with decreases in JAK2 and p-STAT3/STAT3 in placental tissues of PE patients. Additionally, HTR8/SVneo cells in the H/R group had decreased invasion and migration abilities with increased apoptotic rates and oxidative stress levels. Moreover, the expression of miR-133b was up-regulated with decreases in p-JAK2 and p-STAT3 in H/R-treated HTR8/SVneo cells. These indicators in the H/R + miR-133b inhibitor group were ameliorated in comparison with those in the H/R group but deteriorated in the H/R + JAK2 siRNA group. Moreover, JAK2 siRNA reversed the positive effect of the miR-133b inhibitor on the invasion and migration abilities of trophoblasts. In summary, inhibiting miR-133b may improve oxidative stress injury to promote the migration and invasion of trophoblasts and suppress apoptosis by activating the JAK2/STAT3 pathway.

WISP1 promotes bovine MDSC differentiation via recruitment of ANXA1 for the regulation of the TGF-β signalling pathway

Skeletal muscle is one of the most important tissues of the human body necessary for sporting activities. The differentiation of muscle-derived satellite cells (MDSCs) plays an important role in the development and regeneration of skeletal muscles. Similarly, the Wnt/β-catenin signalling pathway plays an important role in the process of muscle differentiation. Wnt1-inducible signalling pathway protein-1 (WISP1), a downstream protein of the Wnt/β-catenin signalling pathway and a member of the CCN family that also plays an important role in the differentiation process, and its expression increase during the differentiation of bovine MDSCs. However, its role in MDSC differentiation is poorly understood. Therefore, we investigated the mechanisms regulating this process via Western blot and immunofluorescence staining. Immunoprecipitation and mass spectrometry detected annexin A1 (ANXA1), a protein that interacts with WISP1. To determine whether WISP1 influences TGF-β signalling and differentiation independently of ANXA1, the latter was knocked down, while WISP1 was activated. WISP1 expression increased significantly during bovine MDSC differentiation. However, WISP1 did not affect the TGF-β signalling pathway protein marker when ANXA1 was inhibited. Taken together, WISP1 regulates the TGF-β signalling pathway through ANXA1 recruitment, thereby promoting bovine MDSC differentiation, suggesting the Wnt/β-catenin signalling pathway as another target to promote cell differentiation.

Annexin A1 accounts for an anti-inflammatory binding target of sesamin metabolites

Sesamin [(7α,7'α,8α,8'α)-3,4:3',4'-bis(methylenedioxy)-7,9':7',9-diepoxylignane] is a major lignan in sesame seeds. Sesamin is converted to the catechol metabolite, SC1 [(7α,7'α,8α,8'α)-3',4'-methylenedioxy-7,9':7',9-diepoxylignane-3,4-diol] with anti-inflammatory effects after oral administration. However, its molecular target remains unknown. Analysis using high-performance affinity nanobeads led to the identification of annexin A1 (ANX A1) as an SC1-binding protein. SC1 was found to bind to the annexin repeat 3 region of ANX A1 with a high-affinity constant (Kd = 2.77 μmol L^-1). In U937 cells, SC1 exhibited an anti-inflammatory effect dependent on ANX A1. Furthermore, administration of sesamin or SC1 attenuated carbon tetrachloride-induced liver damage in mice and concurrently suppressed inflammatory responses dependent on ANX A1. The mechanism involved SC1-induced ANX A1 phosphorylation at serine 27 that facilitates extracellular ANX A1 release. Consequently, the ANX A1 released into the extracellular space suppressed the production of tumor necrosis factor α. This study demonstrates that ANX A1 acts as a pivotal target of sesamin metabolites to attenuate inflammatory responses.

The effects of estradiol on inflammatory and endothelial dysfunction in rats with preeclampsia

Preeclampsia (PE), a hypertensive disorder during pregnancy, has adverse effects to both the mother and the fetus. Maternal inflammatory and vascular endothelial dysfunction are important factors in the pathogenesis of PE. The present study aimed to investigate the effects of estradiol (E2) on inflammatory and endothelial dysfunction in an N (omega)-nitro-L-arginine methyl ester (L-NAME)-induced rat model of PE. Adult pregnant female Sprague-Dawley rats were divided into four equal groups between days 7 and 11 of gestation and treated as follows: i) Pregnant rats receiving daily intraperitoneal (i.p.) injections of equal volume of 0.9% normal saline (NS) (Control group, n=12); ii) pregnant rats receiving daily i.p. injections of L-NAME at 50 mg/kg (L-NAME group, n=12); iii) pregnant rats receiving a daily i.p. injection of 50 mg/kg L-NAME and NS from day 11 (L-NAME + NS group, n=12); and iv) pregnant rats receiving daily i.p. injections of 50 mg/kg L-NAME and 100 µg/kg/day E2 from day 11 (L-NAME + E2 group, n=12). On day 21, blood pressure (BP) and the level of 24-h urine protein in the maternal rats, fetal weight and percentage of stillbirths following a cesarean section were recorded. The activities of nitric oxide (NO) and inducible NO synthase (iNOS), the levels of inflammatory cytokines [interleukin (IL)-1β, IL-6, interferon-γ and monocyte chemoattractant protein-1], adherence factors (CD49d, intracellular adhesion molecule 1 and lymphocyte function-associated antigen-1) and uterine angiogenic status (Fms-like tyrosine kinase-1, vascular cell adhesion molecule and matrix metalloproteinase 2/9) were also assessed. In addition, the histopathology of the placenta, the expression of estrogen receptor α 36 (ERα36), ERα, ERβ and G protein-coupled ER, as well as the activation of the toll-like receptor 4 (TLR4) signaling pathway (TLR4, myeloid differentiation primary response 88, IL-1 receptor-associated kinase 4 and tumor necrosis factor receptor-associated factor 6) were evaluated by H&E staining, immunofluorescence and western blot assays. Treatment with L-NAME increased the BP, urine protein and rate of stillbirths and suppressed fetal weight compared with those in the control group. The L-NAME-induced effects were attenuated by the administration of E2. In addition, the administration of E2 decreased inflammation and NO levels and altered the uterine angiogenic status. The histological analysis of PE rat placenta in the E2-treated group confirmed the effects on biochemical parameters. Of note, E2 treatment significantly suppressed the TLR4 signaling pathway. In the rat model of PE, adverse outcomes including BP, fetal rat weight and proteinuria, high neonatal death rate, inflammatory response, oxidative stress and endothelial dysfunction were attenuated by exogenous E2 administration, which may present a novel approach for the clinical treatment of PE.

Proteomics analysis of the matrisome from MC38 experimental mouse liver metastases

Dissemination of primary tumors to distant anatomical sites has a substantial negative impact on patient prognosis. The liver is a common site for metastases from colorectal cancer, and patients with hepatic metastases have generally much shorter survival, raising a need to develop and implement novel strategies for targeting metastatic disease. The extracellular matrix (ECM) is a meshwork of highly crosslinked, insoluble high-molecular-mass proteins maintaining tissue integrity and establishing cell-cell interactions. Emerging evidence identifies the importance of the ECM in cancer cell migration, invasion, intravasation, and metastasis. Here, we isolated the ECM from MC38 mouse liver metastases using our optimized method of mild detergent solubilization followed by biochemical enrichment. The matrices were subjected to label-free quantitative mass spectrometry analysis, revealing proteins highly abundant in the metastatic matrisome. The resulting list of proteins upregulated in the ECM significantly predicted survival in patients with colorectal cancer but not other cancers with strong involvement of the ECM component. One of the proteins upregulated in liver metastatic ECM, annexin A1, was not previously studied in the context of cancer-associated matrisome. Here, we show that annexin A1 was markedly upregulated in colon cancer cell lines compared with cancer cells of other origin and also over-represented in human primary colorectal lesions, as well as hepatic metastases, compared with their adjacent healthy tissue counterparts. In conclusion, our study provides a comprehensive ECM characterization of MC38 experimental liver metastases and proposes annexin A1 as a putative target for this disease.NEW & NOTEWORTHY Here, the authors provide an extensive proteomics characterization of murine colorectal cancer liver metastasis matrisome (the ensemble of all extracellular matrix molecules). The findings presented in this study may enable identification of therapeutic targets or biomarkers of hepatic metastases.

Functional secretome analysis reveals Annexin-A1 as important paracrine factor derived from fetal mesenchymal stem cells in hepatic regeneration

BACKGROUND

Human mesenchymal stem/stromal cells (MSCs) and their secreted molecules exert beneficial effects in injured tissues by promoting tissue regeneration and angiogenesis and by inhibiting inflammation and fibrosis. We have previously demonstrated that the therapeutic activity of fetal MSCs derived from amniotic fluid (AF-MSCs) and their hepatic progenitor-like cells (HPL) is mediated by paracrine effects in a mouse model of acute hepatic failure (AHF).

METHODS

Herein, we have combined proteomic profiling of the AF-MSCs and HPL cell secretome with ex vivo and in vivo functional studies to identify specific soluble factors, which underpin tissue regeneration in AHF.

FINDINGS

The anti-inflammatory molecule Annexin-A1 (ANXA1) was detected at high levels in both AF-MSC and HPL cell secretome. Further functional analyses revealed that the shRNA-mediated knock-down of ANXA1 in MSCs (shANXA1-MSCs) decreased their proliferative, clonogenic and migratory potential, as well as their ability to differentiate into HPL cells. Liver progenitors (oval cells) from AHF mice displayed reduced proliferation when cultured ex vivo in the presence of conditioned media from shANXA1-MSCs compared to control MSCs secretome. Intra-hepatic delivery of conditioned media from control MSCs but not shANXA1-MSCs reduced liver damage and circulating levels of pro-inflammatory cytokines in AHF.

INTERPRETATION

Collectively, our study uncovers secreted Annexin-A1 as a novel effector of MSCs in liver regeneration and further underscores the potential of cell-free therapeutic strategies for liver diseases. FUND: Fondation Santé, GILEAD Asklipeios Grant, Fellowships of Excellence - Siemens, IKY, Reinforcement of Postdoctoral Researchers, IKY.

Aflatoxin B1 Induces Immunotoxicity through the DNA Methyltransferase-Mediated JAK2/STAT3 Pathway in 3D4/21 Cells

As the most toxic mycotoxin of all of the fungal toxins, aflatoxin B₁ (AFB₁) has carcinogenesis, heptotoxicity, and immunotoxicity. DNA methylation plays a critical role in gene expression regulation of the pathological process. However, the relationship between DNA methylation and AFB₁-induced immunotoxicity was not yet reported. Therefore, the objectives of this study were to verify AFB₁-induced immunotoxicity and investigate the potential role of the DNA methyltransferase (DNMT) family in AFB₁-induced immunotoxicity and the pathway mechanism in 3D4/21 cells. The results showed that AFB₁ could induce cytotoxicity, apoptosis, pro-inflammatory cytokine expression, DNA damage, and oxidative stress and decrease phagocytotic capacity. Meanwhile, the levels of DNMT1 and DNMT3a were significantly increased in 0.04 and 0.08 μg/mL AFB₁ compared to the control. Inhibition of DNMT1 and DNMT3a by 5-Aza-2dc could reverse changes of the above parameters. Further, the JAK2/STAT3 pathway was significantly activated in 0.04 μg/mL AFB₁. Inhibition of p-JAK2 and p-STAT3 by AG490 could alleviate AFB₁-induced immunotoxicity. Moreover, inhibition of DNMT1 and DNMT3a by 5-Aza-2dc could suppress the phosphorylation of JAK2 and STAT3. Taken together, AFB₁-induced immunotoxicity is related to the JAK2/STAT3 pathway mediated by DNMTs in 3D4/21 cells.